ciągi jula: Oblicz 2a₅ − b₇ a₁ = 0,5 a_n+1 = (−2)_n * a_n dla n≥1 b₁ = 0 b_n+1 = b_n − (−1)_n dla n ≥1

janek191: a₁ = 0,5 a₂ = (−2)¹*a₁ = −2*0,5 = − 1 a₃ = (−2)²*a₂ = 4*(−1) = − 4 a₄ = (−2)³*a₃ = − 8*(−4) = 32 a₅ = (−2)⁴*a₄ =16*32 = 512 b₁ = 0 b₂ = b₁ − (−1)¹ = 0 + 1 = 1 b₃ = b₂ − (−1)² = 1 − 1 = 0 b₄ = b₃ −(−1)³ = 0 +1 = 1 więc b₅ = 0 b₆ = 1 b₇ = 0 zatem 2 a₅ − b₇ = 2*512 − 0 = 1024